Printing process and ink therefor



Patented Dec. 31, 1940 PRINTING PROCESS AND INK THEREFOR Ralph T. K. Cornwell, Fredericksburg, Va., assignor to Sylvania Industrial Corporation, Fredericksburg, Va., a corporation of Virginia No Drawing. Application January 7, 1939,

Serial No. 249,729

15 Claims.

first has been of the so-called flash drying" type which has enabled the pellicles to be rapidly printed and stacked one on top of the other without smearing, but this type of ink has not been capable of tightly anchoring itself to the pellicles so that it could withstand immersion in water for any substantial length of time without separating from. the pellicle. The second type of ink has been of the water-resistant type which is capable of anchoring itself to the pellicles so asto remain attached when the same is immersed in water,

but this type has always been slow drying which has made it impossible to print continuously or to stack printed pellicles one on top of the other or to permit the printed surfaces of the pellicles to come in contact with any other object for several hours following printing. This has necessitated printing the pellicles in separate sheets or short pieces and the use of separators; commonly called slip-sheets," betweenthe sheets or pieces if they were stacked one on top of the other to prevent the printed surfaces from smearing or off-setting. Such printing procedures have been slow and consequently expensive.

It is a general object of the present invention to provide a process of printing pellicles.

It is a specific object of the present invention to provide a process of printing water-swelling, non-fibrous pellicles with a quick-drying ink to give a deposit which is immediately non-tacky 40 and is also adherent when the printed pellicle is immersed in water.

It is a further object of the present invention to provide an ink which is quick-drying and capable of producing a deposit which is non-tacky and capable of adhering tenaciously to a water-swell ing pellicle when the same is immersed in water as well as when it is subsequently dried.

, It is a still further object of the present invention to provide an ink which is quick-dryingand 50 which after a short period will tenaciously adhere to a water-swelling pellicle when the same is immersed in water as well as when it is subsequently dried.

It is still another object of the present inven- 55 tion to provide an article of manufacture in the form of a water-swelling non-fibrous pellicle provided with a printed area or areas which will adhere to the pellicle during submersion of the same in water and duringand after subsequent drying.

Other objects of the invention will in part be obvious and will in part be pointed out in the following detailed description.

In accordance with the present invention a nontacky and strongly adherent design is produced on plasticized non-fibrous pellicles, preferably of the water swelling type, by printing the dry surface thereof with an ink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a quantity of a hard resin sufficient to give .a non-tacky ink deposit upon the evaporation of the ink vehicle, a coloring matter and a volatile organic vehicle for the ink, and

, ings and the like formed of nonfibrous organic plastic materials. The designs may be formed on the surface of the dry pellicle by any suitable printing method such as typography or intaglio process and, if desired, the printing process may be carried out on a continuously operated printing press such as a rotary press. The printed material isthen treated to evaporate the ink sol vent and finally wound upon a suitable roller or severed into desired lengths. The printed-pellicle 35 is then aged, for example, for a period of twentyfour hours or longer to harden the drying oil or synthetic resin having drying characteristics. After the ink base has hardened, the ink deposit will adhere tenaciouslyto the pellicle when it is 40 immersed in water as well as when the pellicle is later dried.

The invention accordingly comprises the several steps and relation 'lf one or more of such steps with respect to each of the others, and the composition of matter and article possessing the features, properties, and the relation of elements, which are exemplified in the following detailed disclosure, and the scope of the invention will be indicated in the claims.

Pellicles which may be advantageously ornamented in accordance with the present invention may be formed of non-fibrous organic plastic material such as a non-fibrous cellulosic material, for example, cellulose hydrate regenerated, from 55 cle which is especially applicable for use with the present invention is plasticized cellulose hydrate, commonly known as Cellophane.

The pellicles may be plasticized with any well known type of plasticizer depending upon the nature of the pellicle. It is preferred, however, that the pellicles be plasticized with one of the following materials: glycerol, sorbitol, sugar solutions, the glycols such as diethylene glycol, or a suitable mixture of these substances. I

To condition the surface of the pellicle for printing, the plasticized pellicle is either completely dried to the-condition of the dried articles of commerce, or the superficial parts of the plasticized pellicle are dried so that the surface is non-tacky and free of any liquid which will interfere with the wetting of the'pellicie by the ink, or which will detract from the adherence of the ink deposit. In other words, the surface of the pellicle at the time of printing should be free of liquid and in a dry state although the interior of the pellicle need not be fully dried. I

For the ink base employed in the present in vention there is used a film-forming ink base selected from thegroup consisting of drying oils and synthetic resins having drying characteristics. Among the drying oils which may be employed are linseed oil, China-wood or tung oil, Perilla oil, poppy oil, menhaden oil, sardine oil, and synthetic oils of an ester formed by the reaction of glycerin and an unsaturated fatty acid, for example, an ester sold under the trade name Nee-Fat, etc. and combinations of such oils.

The treatment of the oil to make it rapidly drying does not form an essential part of this invention since rapid drying oils are commonly .known and. may be prepared by heat'treatment such as boiling or by blowing 'airthrough the oil or by adding commercial driers (siccatives) to' the oil to increase its rate of oxidation or polymerization. I I r I For the synthetic resins having drying charac- I teristics there may be employed any oil modified synthetic resin, such for example as alkyd resins, phenol formaldehyde resins, glyptal resins, and the like, and mixtures of such resins, which have been formed in the presence oi drying oils as is I well known in the art. The resulting oil modified resin has drying characteristics similar to the drying oils above mentioned and for the purpose of the invention may be considered equivalent to the drying oil. However, the oil modified resins having drying characteristics should not be confused with the synthetic resins produced in the absence of drying oils and which do not have drying characteristics. The oil modified syn" thetic resins having drying characteristics are capable of forming hard, non-tackyfilms upon ageing and the drying rate of such resins may be accelerated by the use of commercial driers (siccatives) as is well known in the art. The inven- To facilitate the drying of the ink base, that is the evaporation of the drying oil or of the synthetic resin having drying characteristics, there is preferably employed in the ink a commercial drier or siccative. Such agents are oxidizing substances which when added to the ink hasten the hardening of the ink base. Among the siccatives which may be employed are resinates of lead. manganese, zinc, cobalt and/or manganese borate, cobalt linoleate, oleate dioxide, and the like. The amount of siccative to be added will depend upon the particular drying oil or synthetic resin employed and therate of hardening desired. For the resin employed to render the ink deposit immediately non-tacky upon the evaporation of the volatile solvent. there may be used either a natural or synthetic hard resin. Among the natural resins which are'capable of use in the present invention are copal, shellac and ester gum.

Among the synthetic resins are glyptal resin, such as that sold under the trade name Becks.- pol" or Beckacite, polymerized acrylic acid and its derivatives, phenol condensate resin, such as that sold underthe trade name Amberol, chlorinated biphenyl resins, such as those sold under the trade name Aroclors," and coumarone resins, such asthose sold under the trade name "Cumar." I I If desired, suitable unsaponiflable waxy or greasy materials, such as, paraffin and/or petroleum jelly may be added to the above ingredients as well as spar varnish and suitable thickeners, such as a water soluble cellulose ether, starch and dextrine. The unsaponlfiable waxy or greasy I material tends to render the ink additionally resistant to water, the spar varnish enhances the adhesive qualities of the ink and the thickener provides a convenient material for controlling the consistency ofthe ink. In addition there may be 'addedto the ink a hard wax such asmontan or carnauba or synthetic hard waxes such as the product sold under the trade name Halowax." The hard wax tends to render the ink deposit less tacky and imparts to the design a desirable there may be employed any suitable inorganic pigment, such for example as lithopone, titanium dioxide, antimony oxide, whiting, lamp black and the like, ororganic pigments, such for example as Prussian blue, ultramarine blue, Chinese blue, and the like, and/or' any suitable dyestuils as are well known in the art. The ink may contain also wetting agents, dispersion agents and thickening agents as well known in the art. I

For printing all classes of non-fibrous organic plastic materials which must undergo changes in dimension during use, it is desirable to render the ink deposit sufliciently flexible to follow the changes in dimension of the base material. For

this purpose there may be added to the ink composition a suitable plasticizer for thefilm-i'orming ink base suchfor example as castor oil, butyl stearate, dibutyl phthalate, ethyl lactate and the like.

, For the liquid vehicle of the ink there may be employed a volatile organic solvent of the filmforming ink base which is preferably also a solvent of, the hard resin and of, the other solid ingredients. However, if the solvent of the filmforming ink base is'not a solvent of the hard resin or of the other solid ingredientaadditional specific volatile organic solvents for such other ingredients may be added to the ink base solvent.

P In addition there may be present in the liquid vvehicle an organic liquid diluent which has a high volatility at the temperature used for evaporating the ink vehicle. At least one component of the liquid vehicle should be a liquid which wets ,the surface of the material to be printed: The

.ink base @and/or resin solventsmay be selected from ,thevolatile aliphatic or aromatic hydrocarbons, lower alcohols, lower esters, ethers, and the like,. for example, ethers of diethylene glycol (carbitolior hydrogenated napthalene (tetralin) In the :now preferredembodiment of the invention,

the ink solvent comprises a mixture of toluene, butyl alcohol, and ethers of ethylene glycol, to w'hlch' may be added suitable volatile diluents depending upon the particular ink composition.

The ink vehiclemust be capable of being rapidly evaporated, that is flash dried, at temperatures which do not embrittle the non-fibrous material and leave the composition dry,

hard and non-tacky. The general consideration is that the ink solvent must have a higher vapor pressure-during drying than the vapor pressure of .the mixture of plasticizer and ,water at the surface of the non-fibrous material. Sincethe water in the non-fibrous material is usually accompanied by a hygroscopic substance so as to form a plasticizer which is relatively non-volatile,

the mixture is disposed to a large extent within 1 the material so that surface evaporation is re- I duced, to a minimum. It is possible therefore to subject the ink deposit on the surface of a plasticized water-swelling material to a heat source sufficient to raise-the ink temperature above theboiling point of water without removing any appreciable amount of water from the printed material.

It is consequently possible to use ink vehicles which are not substantially completely evaporated until the ink temperature reaches 150 ,C., but it is preferred that the aforementioned solvents be used. Accordingly, the freshly printed material is treated to evaporate the ink vehicle by exposing it to an air stream having a temperature of 80 to 90 C. for four or five minutes, or even at room temperature if the velocity of the drying air stream is increased.

Alternately, the wet ink deposits may be flash dried by subjecting the ink deposits to a temperature of up to 150 C. for a few seconds as by passing a hot-airblast rapidly over the material.

I By way of explanation of the invention, but

not by way of limitation the following will be given as a general range ofingredients suitable for use in the ink of the invention, the'parts beingby weight:- 1

Film forming'ink base 40 to 70 Hard resin 30 to Siccative 0.02 to 0.1

- Coloring matter as desired.

J By way of illustration, but not by wayof limiting theinvention the following specific examples The ink of. the present invention maybe advantageously used to ornament the surfacesof water-swelling materials by using it to print the surfaces with designs, configurations, solid or mixed colors, pictorial illustrations and the like.

The use of ahard resin and a flash drying solvent in this manner in an oil base combines all of the advantages of an oil base ink'on the one handandof a flash-drying ink on the other hand without: the disadvantages heretofore encountered with each.v Therefore, the present oil base ink combines the desirable properties of an oil base ink,specificallyyadherence of the inkdeposit to the cellulose during immersion in water,

and a.desirable property of the flash-dry ink in that the -.deposit qis immediately track-free.

Since the solvent is-. volatile, at temperatures which do not deleteriously affect the non-fibrous I material the ink is flash-drying which makes it possible to; rapidly; print; non-fibrous pellicles without the use ,of slip sheets=and with absolute freedom: from danger of smearing or offsetting. Also, -the oil, basev which has=hitherto rendered the ink slow drying causes the ink to be resistant to water, and enables the ink'to tenaciously adhere to thefnon-fibrous material when immersed in water and dried. Pellicles so printed can be subjected to; the rigorous treatment usually as- .sociated with meat cookingand curing processes without afiectingthe printing'. V The inkof. thepresent invention is capable of extensive application since non-fibrous pellicles are frequently subjected to conditions which makeit impossible to use inks'hitherto known.

For example, container closures such'as those frequently used-on liquor, perfume and medicine bottles, are customarily soaked in water or some other swelling medium prior to their application to containers. 5 After they-have been applied over the openings of containe s; they are permitted to dryand shrink into tight contact with the container? Itisjof course, necessary that printf ing inks used on such articles be capable, of tenaciously adhering to the non-fibrous material throughout'the entire process of application in order that it will be legible and attractive. It is also necessary that such articles be produced at a rapid rate in order to prevent their becoming prohibitively expensive. "The contrast is apparent between such" tedious and expensive printing operationsand the" printing operations which can beperformed with the ink of the present invention wherein non-fibrous material.

may be printed in continuouslengths and im; mediately wound into rolls or severed and stacked.

one upon another so asvto requirea verysmall storage space; Since the period over which the ink deposit becomes .;resistant to water is short, being in the neighborhood of twenty-four hours,

the amount of storage space is further reduced to an absolute minimum and a waiting period between the'printing of the non-fibrous material and the ultimate'use of the material is pracul ti'cally eliminated since this. period can be. used 9 to ship or otherwise deliverthe printed non-fi br'ous material to the points at which it is to be applied tdcontainers, used as meat or otherfood containers, etc.

The invention is particularly applicable for the printing of designson endless tubing adaptedto be usedas sausagecasings. Such tubings may bejormed of cellulose hydrate regenerated from viscose orby the deestcriflcation of nitrocellulose and the like. To prepare the tubing for printing,

it is softened and dried in the usual manner to produce a commercially dried product and the dried tubing is then printed with the in]: of the invention and the liquid vehicle evaporated by flash drying as above described. The flash dried ink deposits are immediately non-tacky and the tubing may be rolled upon itself. The printed material is then aged for a short period of time. about three to four days, during which the'filmforming oil base hardens' and rendersthe ink deposit stronglyadherent and resistant to peeling in the presence of water as during thesoaking of the casings and the cooking of the sausage.

In the printing of endless tubing which is to be cut transversely into short bands'fonuse as container closures it is necessary to prevent the irreversible shrinkage on dryingof the material so that the printed material will retain its tendency to swell in water and shrink again upon drying asis necessary when the band is'used as a shrinkable containeraclosure; To maintain the shrinking characteristics the tubing is taken in the gel state before drying and plasticized with a large quantity ofa .water solubleplasticizer such as glucose, sorbitol, diethylene glycol, or the like, and then dried carefully to produce a liquid free surface, but not to completely dehydrate the material. After the printing of the uubing and the ageing of the ink deposit, the tubing may be soaked in water whereupon the plasticizer is dissolved out. and water is imbibed bythe tubing. Theswollen tubing will be found to have substantially the same swelling and by printing, the steps comprising printing a ,de-

shrinking characteristics as the original tubing in the gel state. v a i Since certain changes in carrying out the above processes and certainmodiflcations in the article and composition which embody theinvention may be made without departing from its scope, it is intended that all matter contained in the foregoing description shall be interpreted as illustrative and not in aiimiting sense.

The invention having been described, what is claimed is:

1. In a process of surface omamentation of a pellicle formed of non-fibrous organic material sign on the surface of the pellicle with anink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a flash-drying vehicle for the ink, and a hard resin to give a non-tacky ink deposit upon the evaporation of the vehicle, evaporating the ink vehicle and ageing the printed pellicle to harden the filmv forming base.

harden the film-forming base.

, 3. In a process of Surface ornamentation of a pellicle formed of non-fibrous organic material by printing, the steps comprising printing a design on the surface of the pellicle with an ink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a siccative,

a flash-drying vehicle for the ink, and a hard resin to give a non-tacky ink deposit upon the evaporation of the vehicle, evaporatingthe ink vehicle and ageing theprinted the film-forming base. i i

4. In a process of surfaceornamentation of a pellicle formed of non-fibrous organic'material by printing, the steps "comprising printing synthetic resins, having drying characteristics,

a coloringmatter, a ,siccative, a flash-drying vehicle for the ink, and a hard resin to given nontacky ink depositupon the evaporation" of the vehicle, evaporating the ink vehicle and ageing the printed pellicle to harden the film-forming base. 1

5. In a process of surface ornamentation of a pellicle formed of non-fibrous organic material by printing, the steps comprising printing a design on the surface of the pellicle with an ink comprising a'film-iorming base selected from the group consistingof drying oils andsynthetic resins havingdry'ing characteristics, a flashdrying vehicle for the ink, a hard resin to give a non-tacky ink deposit 'upon the evaporation of the vehicle, flash-drying the'ink deposit, and ageing the printed pellicle until the ink base has hardened. i

6. In a process of printing sausage casings formed of non-fibrous organic material comprising, drying the surface of the casing and printing a design on the dry surface with an ink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a flashdrying vehicle for the ink, anda hard resin to ive a non-tacky ink deposit upon the evaporationof the vehicle, evaporating the ink vehicle and ageing the printed casing to harden the film-forming base.; i l

7. In a process of printing a shrinkable container closure formed of a non-fibrous organic material comprising plasticizing the closure, drying the surface of the closure, printing on the dry surface with an ink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a flash-drying vehicle for the ink, and a hard resin to give a non-tacky ink deposit upon the evaporation of the vehicle, evaporating the ink vehicle and aging the printed closure to harden the film-forming base. i

8. A printing ink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a flash-drying vehicle forthejink: and a hard resin to give a non-tacky ink deposit upon the evaporation of the vehicle.

9. A printing ink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a coloring matter, a flash-drying vehicle for the ink, and a hard resin to give a non-tacky ink deposit upon the evaporation of the vehicle.

10. A printing in]: comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a siccative, a flash-drying vehicle for the ink, and a hardresin to give a non-tacky ink deposit upon the evaporation of the vehicle.

11. A printing ink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characpellicle to harden 12. A printing ink comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics in an amount of from 40 to 70 parts by weight, a hard resin in an. amount of from 30 to 60 parts, and a flash-drying vehicle for theink, the resin rendering the ink deposit nontacky upon evaporation of the vehicle.

13. An ink for printing films, sheets, bands or tubing formed 01' non-fibrous organic material comprising a film-forming base selected from the group consisting of drying oils and synthetic resins having drying characteristics, a flash-drying vehicle for the ink, and a hard resin to give a. non-tacky. ink deposit upon the evaporation of the vehicle.

14. In a process of surface ornamentation by printing, the steps comprising printing a design on the surface of a peilicie with an ink comprising a film-forming base selected from the group 1 consisting of.drying oils and synthetic resins having drying characteristics, a flash-drying vehicle for the ink, and a tack-reducing agent to render the ink deposit non-tacky upon the evaporation of the vehicle, evaporating the ink vehicle and ageing the printed p'ellicie to harden the filmforming base.

15, A printing ink comprising a film-forming I 

